Coefficient of Variation Masking: A Volatility-Aware Strategy for EHR Foundation Models

Fuente: arXiv
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Autori principali: Fani, Rajna, Attrach, Rafi Al, Restrepo, David, Jia, Yugang, Celi, Leo Anthony, Schüffler, Peter
Natura: Preprint
Pubblicazione: 2025
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author Fani, Rajna
Attrach, Rafi Al
Restrepo, David
Jia, Yugang
Celi, Leo Anthony
Schüffler, Peter
author_facet Fani, Rajna
Attrach, Rafi Al
Restrepo, David
Jia, Yugang
Celi, Leo Anthony
Schüffler, Peter
contents Masked autoencoders (MAEs) are increasingly applied to electronic health records (EHR) for learning general-purpose representations that support diverse clinical tasks. However, existing approaches typically rely on uniform random masking, implicitly assuming all features are equally predictable. In reality, laboratory tests exhibit substantial heterogeneity in volatility: some biomarkers (e.g., sodium) remain stable, while others (e.g., lactate) fluctuate considerably and are more difficult to model. Clinically, volatile biomarkers often signal acute pathophysiology and require more sophisticated modeling to capture their complex temporal patterns. We propose a volatility-aware pretraining strategy, Coefficient of Variation Masking (CV-Masking), that adaptively adjusts masking probabilities according to the intrinsic variability of each feature. Combined with a value-only masking objective aligned with clinical workflows, CV-Masking yields systematic improvements over random and variance-based strategies. Experiments on a large panel of laboratory tests show that CV-Masking enhances reconstruction, improves downstream predictive performance, and accelerates convergence, producing more robust and clinically meaningful EHR representations.
format Preprint
id arxiv_https___arxiv_org_abs_2512_05216
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Coefficient of Variation Masking: A Volatility-Aware Strategy for EHR Foundation Models
Fani, Rajna
Attrach, Rafi Al
Restrepo, David
Jia, Yugang
Celi, Leo Anthony
Schüffler, Peter
Machine Learning
Masked autoencoders (MAEs) are increasingly applied to electronic health records (EHR) for learning general-purpose representations that support diverse clinical tasks. However, existing approaches typically rely on uniform random masking, implicitly assuming all features are equally predictable. In reality, laboratory tests exhibit substantial heterogeneity in volatility: some biomarkers (e.g., sodium) remain stable, while others (e.g., lactate) fluctuate considerably and are more difficult to model. Clinically, volatile biomarkers often signal acute pathophysiology and require more sophisticated modeling to capture their complex temporal patterns. We propose a volatility-aware pretraining strategy, Coefficient of Variation Masking (CV-Masking), that adaptively adjusts masking probabilities according to the intrinsic variability of each feature. Combined with a value-only masking objective aligned with clinical workflows, CV-Masking yields systematic improvements over random and variance-based strategies. Experiments on a large panel of laboratory tests show that CV-Masking enhances reconstruction, improves downstream predictive performance, and accelerates convergence, producing more robust and clinically meaningful EHR representations.
title Coefficient of Variation Masking: A Volatility-Aware Strategy for EHR Foundation Models
topic Machine Learning
url https://arxiv.org/abs/2512.05216